An oral surgical instrument (osteotome) of a generic type is known from DE 43 16 955 A1. This instrument is used for the surgical splitting and spreading of sections of the jaw for the implantation of implants that have a circular cross section, especially in the upper jaw. The drawback in this case is a relatively great length of the osteotomy line because of the slot shape of the opening that is created in the jaw. This frequently leads to postoperative loosening of the implant or to a poor healing of the wound. This is supposed to be avoided with the better working tip of the anticipated dental instrument, which can be adapted to the jaw ridge, but a relatively high operating expense is necessary when using the anticipated dental instrument in order to implant an implant for the fixation of tooth crowns.
On the other hand, the creation of jaw openings for the implantation of implants by means of drilling is well known in dentistry. As a result of this, however, valuable bone material is removed, due to which the fitting strength of the implant is not guaranteed. It is well known in dentistry that the bone material of the upper jaw is considerably softer than the bone material of the lower jaw, whereby the bone material of the upper jaw may be compared with balsa wood in terms of its strength. The bone material is divided into a plurality of bone classes, whereby even osteoporosis, i.e., the structural change of the bone material in old age, is taken into consideration. Especially with regard to the softness of the bone material of the upper jaw, the drilling for the formation of openings in the upper jaw for the implantation of implants proves to be extremely unfavorable, since bone material is still removed from the soft bone material anyway.
An instrument (osteotome) according to Summers, which comprises a handle-like holder and a shaft with a working tip having a circular cross section, and which is provided with graduated rings on its shaft that are directly connected to the working tip and with a concave spherical cap on its end, has previously become known especially for the formation of openings in the upper jaw for the implantation of implants. Summers' osteotomes have the shape of a graduated round rod. They are available in six sizes with increasing diameters. In each case, the next largest instrument is inserted into the jaw opening formed. The implant bed is created by means of expanding and compressing the bone material. The working end of the instruments is concave and is bordered with sharp edges. The penetration depth of the instruments is determined by means of markings. By pressing in the dental instrument to form the opening, the bone material of the upper jaw is displaced and compacted. The bone material expands after pulling out the dental instrument and after implanting the implant and it holds onto this. In the ensuing time, new bone material is formed around the implanted implant. Thus, no bone material is removed in this method of implantation, but the bone material, especially of the soft upper jaw, is, in contrast, absolutely compacted. However, the drawback thereby is the formation of simple, slightly conical cavities in the jaw, especially in the upper jaw, which do not guarantee a reliable bed for the fixation especially of screw-type implants. Especially since prior-art implants have different outer contours, e.g., graduated cylinder implants with and without screw threads, as well as cylinder implants with and without partial or continuous screw threads, the conventional, slightly conical, oral surgical instruments according to Summers are unable to guarantee that the slightly conical opening formed in the jaw will reliably hold the implanted implant.